The present invention relates to a method of generating and/or providing data for tissue treatment, in particular for tumor treatment, by means of a radiation device.
Current methods of treating tumors provide for example, that the tumor is first excised by surgery and that the remaining edge tissue around the tumor is subsequently irradiated. It is also possible, that the tumor is fought by irradiation only without necessitating surgery.
When carrying out irradiation, it is crucial that the irradiation appliance is set in an appropriate manner, so that the required irradiation dose and irradiation intensity can be adjusted.
For example, DE 10 2004 039 191 A1 describes a solution, wherein for determination and monitoring of parameters of an irradiation therapy a first image of the tissue, which is to be irradiated, is generated in an image-providing medical technical method. By means of the first image a first parameter setting of the irradiation appliance is carried out. The tissue is irradiated with this parameter setting. In addition, at least one further image of the tissue, which is to be irradiated, is generated. Subsequently, an automatic comparison of the images is carried out and a signal is generated in case of deviations.
It is, for example, known to perform irradiations by means of so called high-energy linear accelerators. Therein the procedure of the planning of tumor irradiations with radiation therapy units, for example with x-ray therapy units, is as follows:
Firstly, an image, for example, a CT- or x-ray image, of a defined area around the tumor is generated in an image-providing method. This image is displayed on a display screen. Then the tumor and/or the tissue, which is to be irradiated, is marked. An irradiation plan is established, via a method, for example by means of appropriate software. To display the dose rate in the body of the patient to the surgeon directly on the image, the generated pictures are overlaid, for example by plotting isodose curves/surfaces/volumes, with values, which were calculated from the irradiation plan.
A disadvantage of this known solution is, that it is not applicable to low-energy irradiation appliances or irradiation methods, respectively. The procedure, which has been described in connection with irradiation via linear accelerator, cannot be used for low-energy systems and applications. Low-energy irradiation appliances are frequently being used in intraoperative methods.
In a system with considerably lower radiation energy, for example x-ray energy, than in systems with linear accelerators, the physical interactions of the low-energy rays with the tissue, which is to be irradiated, are considerably more complex due to the lower energy of the rays. This means, that different types of tissue weaken the rays to different degrees. This may be due to, for example, the so called photo- or Compton-effect. Furthermore, low-energy systems do not represent systems with monochromatic radiation quality. Low-energy systems rather show a very complex radiation spectrum from 0 to the current maximal radiation energy of for example 50 keV. That means, that with an increase in penetration of the radiation of the low-energy irradiation system into the tissue, the weakening even changes with homogenous tissue, as the radiation spectrum changes with increasing absorption in the tissue.
Therefore, the approach which is known in connection with linear accelerators cannot successfully be used with low-energy irradiation systems, as otherwise thereby large deviations of the calculations from the true value of the dose in the patient would occur.